The present invention relates generally to synthetic substitutes for edible oils, such oils containing fatty alcohol esters. The chosen fatty alcohol esters have a low caloric value which makes them suitable for the commercial production of calorie-reduced fried snack foods. More particularly, the present invention is directed to low-calorie fatty alcohol esters of succinic acid and their use in low calorie cooking oil compositions.
Lipids (fats and oils) constitute between 30 and 40% of the caloric intake of the average American diet. Dietary fat, consisting of triglycerides, is digested to free fatty oils and monoglycerides primarily in the small intestine. The .alpha.-lipase steapsin cleaves the glycerol esters at the 1- and 3- positions. Fatty acids of 6 to 10 carbons and unsaturated fatty acids are rapidly absorbed, while those of 12 to 18 carbons are absorbed more slowly. Absorption of the .beta.-monoglycerides by the mucosa of the small intestine results in a final digestion and absorption of up to 95% of the total dietary fat. Since fats yield about twice the energy per gram of either carbohydrates or proteins, substitution of a non-digestible material for a portion of the normal dietary fat offers an attractive and effective method for reducing total caloric intake and the control of obesity, hypertension, and other diseases associated with excessive caloric intake.
For successful commercial application, a material provided as a dietary fat substitute should be inexpensive, taste good, perform the processing functions of fat, have low calorie content (i.e. the material should be less than 40% absorbed), and must be safe for human consumption. To be inexpensive, the substitute materials should be under current manufacture, or synthesized from materials under current manufacture by a minimum number of processing steps.
Most of the current dietary fat substitutes are fatty acid esters, but fatty alcohol esters also are known. U.S. Pat. No. 4,508,746, issued to Hamm in 1985, describes long chain fatty alcohol esters of citric and tricarballylic acids. The citric acid esters lack thermal stability, however, and the tricarballylic acid starting material is not believed to be produced in commercial quantities.
U.S. Pat. Nos. 4,582,927, and 4,673,581, issued to Fulcher in 1986 and 1987, respectively, describe alkylmalonic and dialkylmalonic acid esters of long chain fatty alcohols, as well as their use in reduced calorie edible oils. These substituted malonic acids are not commercially available and their synthesis from diethyl malonate is relatively expensive at the current time.
U.S. Pat. No. 4,830,787, issued to Klemann et al. in 1989, describes hydroxysuccinic (malic) acid esters which contain both fatty acid and fatty alcohol esters. Despite low raw material cost, the product is expensive because separate esterification steps are required for the two ester types.
U.S. Pat. No. 4,888,195, issued to Huhn et al. in 1989, describes fatty alcohol esters of dicitrate ether, diisocitrate ether and citrate isocitrate ether and esters of polycarboxylic acid ethers containing 4 to 6 ester groups. The three step synthesis involved in the production of these compounds makes them cost prohibitive.
U.S. Pat. No. 4,959,465, issued to Klemann et al. in 1990, discloses succinate-extended sucrose which is further extended with hydroxyl-dicarboxylic acid esterified to two fatty alcohols. A minimum of three synthesis steps are required in preparing these compounds and the use of 3-hydroxyglutaric acid as a reaction substrate make these compounds prohibitively expensive.
Thus, there presently remains a need for inexpensive and stable synthetic substitutes for edible oils suitable for the commercial production of calorie-reduced fried snack foods.